The U.N. World Food Program says it will begin to airlift food to the drought-stricken Horn of Africa on Wednesday.

WFP director Josette Sheeran told VOA Tuesday the first flights will head to Somalia's capital, Mogadishu. The airlift was scheduled to begin Tuesday, but the flights were held up by logistical problems in Kenya.

Definition of Famine:

The word famine is a term that is not used lightly by humanitarian organizations. The United Nations describes a crisis as a famine only when the following conditions are met:

Malnutrition rates exceed 30 percent

More than two people per 10,000 people are dying each day

Severe lack of food access for large population

Current Famine:

Almost half of Somalia's population, 3.7 million people, are affected by the current crisis with malnutrition rates in southern Somalia the highest in the world, surpassing 50 percent in some areas. The United Nations says it is likely that tens of thousands have already have died, the majority of those being children.

The drought that has led to the current famine in parts of Somalia has also affected people in Kenya and Ethiopia.

Previous Famines in the Horn of Africa:

Somalia 1991-1992

Ethiopia 1984-1985

Ethiopia 1974

The WFP had said Monday planes will carry food to Mogadishu, eastern Ethiopia, and northern Kenya, near the Somali border. Sheeran said the U.N. agency is calling in resources and personnel from other parts of the world to respond to the crisis.

U.N. and U.S. officials have said more than 11 million people are in need of emergency aid to survive.

In Somalia alone, Sheeran said about one-third of the population is facing starvation - and she said people tell of having to leave dying family members behind as they continue their long journeys in search of help.

Access to southern Somalia - where the U.N. formally declared a famine last week - has been hampered by the militant group al-Shabab. The group controls large sections of the region and has denied that a famine is taking place.

On Tuesday, the U.N. refugee agency said 100,000 Somalis have arrived at Mogadishu-area camps in the past two months, and continue to come at a rate of 1,000 per day.

It says hundreds of thousands of others have fled to camps in neighboring Kenya and Ethiopia.

The U.N. is planning a donors' conference Wednesday in Kenya's capital, Nairobi. The international body says “massive” action is needed to help the drought victims, many of whom are children. It is seeking pledges of $1.6 billion.